Video signal recording and reproducing apparatus

ABSTRACT

The video signal recording and reproducing apparatus of the invention includes: a receiving section for receiving a television signal; an image compression section for compressing an amount of information per unit time of the received continuous video signal; a writing section for intermittently writing a compressed video signal, obtained as an output of the image compression section, onto a hard disk apparatus via a magnetic head; a reading section for intermittently reading out the written compressed video signal from the hard disk apparatus via the magnetic head; a decoding section for restoring the read compressed video signal into an original video signal; a display section for displaying the restored video signal; and a control section for controlling the writing section and the reading section such that writing the video signal onto the hard disk apparatus and reading an arbitrary video signal, which was previously written onto the hard disk apparatus, from the hard disk apparatus are performed apparently simultaneously and continuously.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a video signal recording andreproducing apparatus which can simultaneously record and reproduce avideo by using a disk apparatus.

2. Description of the Related Art

A video tape recorder (VTR) has heretofore been used as a home-use videorecording apparatus. As is well known, a VTR receives a broadcastprogram transmitted by a broadcasting station via an antenna, recordsthe program and then reproduces the program. That is to say, having oncefinished the recording operation of a predetermined program, the VTRrewinds the tape on which the program has been recorded and thenreproduces the received and recorded program to be watched.

A currently available VTR cannot record and reproduce a videosimultaneously. For example, assuming that a broadcast program whichstarts at 10 o'clock and ends at 12 o'clock is now being received andrecorded by a single VTR, it is impossible to reproduce and watch thebroadcast program from the beginning from 11 o'clock on, whilecontinuing receiving and recording the program. It is much lessimpossible to perform a trick play reproducing operation (e.g., afast-forward reproducing operation or a backward reproducing operation)of a recorded video of a program which is now being received andrecorded. On the other hand, a technique which is called “followingreproducing operation” is currently utilized for a live broadcastrelayed by a broadcasting station. In accordance with this technique, avideo which has been transmitted to a broadcasting station is slightlydelayed and then delivered substantially in real time. However, in sucha case, it is necessary to use either a plurality of VTRs or an opticaldisk apparatus of a special type in which a recording head and areproducing head are separately provided, for simultaneously performingthe recording and the reproducing operations. If a plurality of VTRs aresimultaneously used, then it becomes adversely complicated to operatethese apparatuses. On the other hand, the use of such an optical diskapparatus of a special type disadvantageously increases the costs.

SUMMARY OF THE INVENTION

According to the present invention, a video signal recording andreproducing apparatus is provided. The video signal recording andreproducing apparatus of the invention includes: receiving means forreceiving a television signal; image compression means for compressingan amount of information per unit time of the received continuous videosignal; writing means for intermittently writing a compressed videosignal, obtained as an output of the image compression means, onto ahard disk apparatus via a magnetic head; reading means forintermittently reading out the written compressed video signal from thehard disk apparatus via the magnetic head; decoding means for restoringthe read compressed video signal into an original video signal; displaymeans for displaying the restored video signal; and control means forcontrolling the writing means and the reading means such that writingthe video signal onto the hard disk apparatus and reading an arbitraryvideo signal, which was previously written onto the hard disk apparatus,from the hard disk apparatus are performed apparently simultaneously andcontinuously.

In one embodiment, a compressed video signal which was recorded at anearliest time is sequentially updated by a newly received and obtainedcompressed video signal.

In another embodiment, an audio signal, as well as a compressed videosignal, is recorded onto the hard disk apparatus.

In still another embodiment, the video signal recording and reproducingapparatus further includes instruction means for starting and/orfinishing recording a compressed video signal onto the hard diskapparatus.

In still another embodiment, the video signal recording and reproducingapparatus further includes instruction means for starting and/orfinishing reproducing a compressed video signal from the hard diskapparatus.

In still another embodiment, the instruction means for startingrecording a compressed video signal onto the hard disk apparatus isinstantaneously driven manually.

In still another embodiment, the instruction means for startingrecording a compressed video signal onto the hard disk apparatus isdriven by timer means.

In still another embodiment, the instruction means for finishingrecording a compressed video signal onto the hard disk apparatus isdriven by timer means.

In still another embodiment, the instruction means for startingreproducing a compressed video signal from the hard disk apparatus isinstantaneously driven manually.

In still another embodiment, the display means displays at least a timedifference between a time at which a video signal which is beingreproduced was recorded and a current time, in addition to a video.

In still another embodiment, the display means displays at least acurrent time and a time at which a video signal which is beingreproduced was recorded, in addition to a video.

In still another embodiment, the video signal recording and reproducingapparatus includes operation means for setting a normal reproduction, afast forward reproduction, a backward reproduction or a slowreproduction as a reproduction mode.

In still another embodiment, the display means simultaneously displays areceived video signal and an output of the decoding means which waspreviously recorded, reproduced and decoded.

In still another embodiment, the video signal recording and reproducingapparatus further includes television signal detection means fordetermining whether or not the receiving means has received a normaltelevision signal and writing onto the hard disk apparatus is enabledonly when the television signal detection means has detected a normaltelevision signal.

According to another aspect of the present invention, a video signalrecording and reproducing apparatus is provided. The video signalrecording and reproducing apparatus includes: image compression meansfor digitizing an input continuous video signal and audio signal,thereby compressing an amount of information per unit time; writingmeans for intermittently writing a compressed video signal, obtained asan output of the image compression means, onto a hard disk apparatus viaa magnetic head; reading means for intermittently reading out thewritten compressed video signal from the hard disk apparatus via themagnetic head; decoding means for restoring the read compressed videosignal into an original video signal; and display means for displayingthe restored video signal, thereby reading out predetermined video andaudio signals at a predetermined time.

According to still another aspect of the present invention, a videosignal recording and reproducing apparatus is provided. The video signalrecording and reproducing apparatus includes: image compression meansfor digitizing an input continuous video signal and audio signal,thereby compressing an amount of information per unit time; writingmeans for intermittently writing a compressed video signal, obtained asan output of the image compression means, onto a hard disk apparatus viaa magnetic head; reading means for intermittently reading out thewritten compressed video signal from the hard disk apparatus via themagnetic head; decoding means for restoring the read compressed videosignal into an original video signal; display means for displaying therestored video signal; and sound recognition means for recognizing anaudio signal. In the video signal recording and reproducing apparatus,predetermined video and audio signals are read out at a point of timewhen the sound recognition means recognizes a predetermined sound.

According to still another aspect of the present invention, a videosignal recording and reproducing apparatus is provided. The video signalrecording and reproducing apparatus includes: image compression meansfor digitizing an input continuous video signal and audio signal,thereby compressing an amount of information per unit time; writingmeans for intermittently writing a compressed video signal, obtained asan output of the image compression means, onto a hard disk apparatus viaa magnetic head; reading means for intermittently reading out thewritten compressed video signal from the hard disk apparatus via themagnetic head; decoding means for restoring the read compressed videosignal into an original video signal; and display means for displayingthe restored video signal. In the video signal recording and reproducingapparatus, a video signal at an arbitrary point of time is retrieved foran arbitrary time period by an operation of a viewer from video signalswhich are being received or video signals which were previouslyrecorded, and information for prohibiting overwriting data of theretrieved video signal is added to the retrieved video signal so as tobe stored into the hard disk apparatus.

In one embodiment, when a video signal retrieved by an operation of aviewer is saved, search information required for the viewer to searchfor a desired video signal later is added to the video signal to besaved, and after the video signal which was previously retrieved andsaved has been searched for and read out based on the searchinformation, the read compressed video signal is decoded to be displayedon the display means.

In another embodiment, the video signal recording and reproducingapparatus includes at least an output terminal for outputting digitaldata which has been recorded onto the hard disk apparatus to the outsideof the apparatus. In the video signal recording and reproducingapparatus, a video signal retrieved by a viewer is transferred toanother recording apparatus through the output terminal.

According to still another aspect of the present invention, a videosignal recording and reproducing apparatus is provided. The video signalrecording and reproducing apparatus includes: image compression meansfor digitizing an input continuous video signal and audio signal,thereby compressing an amount of information per unit time; writingmeans for intermittently writing a compressed video signal, obtained asan output of the image compression means, onto a hard disk apparatus viaa magnetic head; reading means for intermittently reading out thewritten compressed video signal from the hard disk apparatus via themagnetic head; decoding means for restoring the read compressed videosignal into an original video signal; and display means for displayingthe restored video signal. In the video signal recording and reproducingapparatus, while compressing a video signal which is being received andwriting the compressed video signal onto the hard disk apparatus, avideo signal which was previously recorded is read out and decoded intoan original video signal, and after an amount of data of the decodedvideo signal has been reduced, the video signal is subjected to an imagecompression again and written onto the hard disk apparatus.

According to still another aspect of the present invention, a videosignal recording and reproducing apparatus is provided. The video signalrecording and reproducing apparatus includes: receiving means forsimultaneously receiving television signals from a plurality ofchannels; image compression means for compressing an amount ofinformation per unit time of the received continuous video signals fromthe plurality of channels; writing means for intermittently writing eachcompressed video signal, obtained as an output of the image compressionmeans, onto a hard disk apparatus via a magnetic head; reading means forintermittently reading out the written compressed video signal from thehard disk apparatus via the magnetic head; decoding means for restoringthe read compressed video signal into an original video signal; anddisplay means for displaying the restored video signal. In the videosignal recording and reproducing apparatus, while compressing videosignals from the plurality of channels which are being received andwriting the compressed video signals onto the hard disk apparatus, avideo signal which was previously recorded from a particular channel isread out.

According to still another aspect of the present invention, a videosignal recording and reproducing apparatus is provided. The video signalrecording and reproducing apparatus includes: receiving means forsimultaneously receiving television signals from a plurality ofchannels; synthesis means for synthesizing the received televisionsignals from the plurality of channels into one screen; imagecompression means for compressing an amount of information per unit timeof the continuous video signal which has been synthesized by thesynthesis means; writing means for intermittently writing a compressedvideo signal, obtained as an output of the image compression means, ontoa hard disk apparatus via a magnetic head; reading means forintermittently reading out the written compressed video signal from thehard disk apparatus via the magnetic head; decoding means for restoringthe read compressed video signal into an original video signal; anddisplay means for displaying the restored video signal. In the videosignal recording and reproducing apparatus, a plurality of video signalsare synthesized into one screen, subjected to an image compression andthen written onto the hard disk apparatus.

By utilizing the above-described configurations, it is possible toprovide an apparatus which can independently perform a trick playreproducing operation (e.g., a fast-forward reproducing operation or abackward reproducing operation) of a recorded part of a broadcastprogram which is now being received, while compression encoding andrecording the broadcast program. As a result, it is possible to startwatching a recorded part of a program without waiting for the program toend as is done in the recording and reproducing operations performed bya conventional single VTR. In addition, even when a viewer initiallystarts watching a program at a time much later than the broadcast starttime of the program, the viewer can finish watching the programsubstantially at the same time as the broadcast end time by additionallyutilizing a fast-forward reproducing function in the middle of thereproducing operation.

According to the present invention, it is possible to provide anapparatus which can perform a normal reproducing operation or a trickplay reproducing operation (e.g., a fast-forward reproducing operationor a backward reproducing operation) of a recorded part of a broadcastprogram which is now being received, while recording the broadcastprogram by using a universal hard disk apparatus without using aplurality of VTRs or an expensive optical disk apparatus for which arecording head and a reproducing head are separately provided. As aresult, it is possible to start watching a recorded part of a programwithout waiting for the program to end, as is necessary in the recordingand reproducing operations performed by a conventional single VTR. Inaddition, even when a viewer initially starts watching a program at atime much later than the broadcast start time of the program, the viewercan finish watching the program substantially at the same time as thebroadcast end time by additionally utilizing a fast-forward reproducingfunction in the middle of the reproducing operation, so that aconsiderable amount of time can be saved. Moreover, in the case where aviewer cannot help stopping watching a program in the middle of theprogram, even if the program still continues when the viewer resumeswatching the program, the viewer can reproduce and watch the programfrom the scene which was broadcast when the viewer left, whilecontinuing recording the program. Furthermore, in the case where aviewer watches a first program while recording a second program on adifferent channel, it is possible to instantaneously start watching thesecond program from the beginning thereof at a time after the firstprogram ends and before the second program ends.

Thus, the invention described herein makes possible the advantage ofproviding a video signal recording and reproducing apparatus which cansimultaneously record and reproduce a television signal.

This and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a configuration for a videosignal recording and reproducing apparatus in a first example of thepresent invention.

FIG. 2 is a diagram illustrating an operational concept in the firstexample.

FIG. 3 is a diagram illustrating the contents of a table RAM.

FIG. 4 is a detailed timing chart of peripheral hardware for a hard diskapparatus.

FIG. 5 is a block diagram illustrating a configuration for a videosignal recording and reproducing apparatus in a fourth example of thepresent invention.

FIG. 6 is a block diagram illustrating a configuration for a videosignal recording and reproducing apparatus in a sixth example of thepresent invention.

FIG. 7 is a diagram illustrating a screen synthesis in the sixth exampleof the present invention.

FIG. 8 is a diagram illustrating a screen separation in the sixthexample of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the embodiments of the present invention will be describedwith reference to the accompanying drawings.

EXAMPLE 1

FIG. 1 is a block diagram illustrating a configuration for a videosignal recording and reproducing apparatus in a first example of thepresent invention. In FIG. 1, the reference numeral 1 denotes anantenna; 2 denotes a tuner; 3 denotes a demodulator; 4 denotes an MPEG1encoder; 5 and 6 denote recording buffer memories; 7 denotes a firstswitch; 8 denotes a hard disk apparatus; 9 and 10 denote reproducingbuffer memories; 11 denotes a second switch; 12 denotes an MPEG1decoder; 13 denotes a TV monitor; 14 denotes a hard disk controller; 15denotes a table RAM; 16 denotes a system controller; 17 denotes a timer;and 18 denotes an operator panel.

First, before describing the operation of the apparatus in the firstexample with reference to FIG. 1, the operational concepts will bedescribed with reference to FIG. 2. In this example, it is assumed thata viewer wants to watch a program which is to be broadcast from 10 p.m.to 12 p.m. (as shown in portion (a) of FIG. 2) but that it is only after11 p.m. that the viewer can watch the program because of someinconvenience. In such a case, in accordance with the method of thisexample, while recording the program from 10 p.m. to 12 p.m. (as shownin portion (b) of FIG. 2), the viewer can start reproducing the programfrom the beginning thereof from 11 p.m. (as shown in portion (c) of FIG.2). When a normal reproducing mode is selected, the reproducingoperation ends at 1 a.m. which is two hours later than the time when theviewer started watching the program. On the other hand, since afast-forward reproducing operation can also be performed on a part ofthe program which has already been recorded as shown in portion (d) ofFIG. 2, it is also possible to reproduce all of the program at a timeslightly later than 12 p.m., that is the time when the broadcasting ofthe program actually ends.

Hereinafter, a detailed operation of the video signal recording andreproducing apparatus of the first example will be described withreference to FIG. 1. First, a viewer pre-sets a TV channel, a recordingstart time and a recording end time of a program to be watched on theoperator panel 18. For example, it is assumed that the viewer sets aprogram on channel # 6 starting at 10 p.m. In such a case, when it is 10p.m., the system controller 16 sets the tuner 2 to channel # 6 inaccordance with the information supplied from the timer 17 such that theelectric waves for the channel # 6 are selected from the electric wavesreceived by the antenna 1, and the demodulator 3 demodulates thereceived waves into signals.

The received signals can be monitored on the TV monitor 13. The receivedsignals are converted by the MPEG1 encoder 4 into compressed videosignals so as to be bit streams having a bit rate of 1.5 Mbps. Thesesignals are transmitted via the first and the second recording buffermemories 5 and 6 having a capacity of 200 Kbytes, for example, and thefirst switch 7 so as to be written onto the hard disk apparatus 8.

This operation will be described in detail later with reference to FIG.3. The sector information indicating the physical positions of thecompressed video signals written on the hard disk and the timeinformation of the written signals are stored in the table RAM 15 so asto correspond to each other. Such a state is maintained until 11 p.m.,when the viewer starts watching the program. When it is 11 p.m., theviewer starts watching the program on the TV monitor 13. In this case,if the viewer wants to watch the program starting at 10 p.m. (i.e.,reserved recording start time) from the beginning thereof, then theviewer has only to push the reproducing button (not shown) on theoperator panel 18.

In this case, the program starting at 10 p.m. is reproduced from thebeginning thereof from 11 p.m. at a normal reproducing speed as shown inportion (c) of FIG. 2. The hard disk controller 14 controls the harddisk apparatus 8 in accordance with the information supplied from thetable RAM 15, so that the compressed video signals recorded on the harddisk apparatus 8 are reproduced via the reproducing buffer memories 9and 10 and the second switch 11. This operation will be described indetail later with reference to FIG. 3. The reproduced compressed videosignals are decoded by the MPEG1 decoder 12 so as to be video signalswhich are displayed on the TV monitor 13.

It is noted that, in this example, the video signals compressed by theMPEG1 encoder 4 are being transmitted via the recording buffer memories5 and 6 and the first switch 7 so as to be continuously written onto thehard disk apparatus 8 until 12 p.m. during the reproduction of the videosignals. When it is 12 p.m., the system controller 16 finishes recordingthe compressed video signals onto the hard disk apparatus 8 inaccordance with the information supplied from the timer 17. In thiscase, it is possible to monitor on the TV monitor 13, the video signalswhich are being written in parallel with the video signals which arebeing reproduced by using a technique such as a screen division.

On the other hand, in performing the reproducing operation, the viewercan reproduce a part of a program to be watched in detail at a slowerspeed and can reproduce an unnecessary part of the program at a higherspeed in accordance with the instructions supplied from the systemcontroller 16 by operating the operator panel 18. The correspondencebetween the sector information of the compressed video signals recordedon the hard disk, and the time information of the signals, has beenstored in the table RAM 15 for performing these operations.

The format of this table is shown in FIG. 3. In FIG. 3, the referencenumeral 19 denotes the time information represented as a time code and20 denotes a sector number on the hard disk. In this example, since eachof a plurality of successive sectors corresponds to one second, sectoraddresses are indicated every other second in FIG. 3. In accordance withthe operation of the viewer, the hard disk controller 14 reproducesrequired video signals based on this time information.

In the case of the MPEG1 standard, an image is generally compressedbased on a unit consisting of a plurality of frames. A concept “GbP(group of pictures)” is used as the unit. For example, in the case where1 GOP=15 frames, 1 GOP covers a video corresponding to 0.5 second. Thus,in the case of performing a fast forward reproducing operation or a slowreproducing operation, if a decimation or an interpolation is performedon a GOP basis with respect to a video which has been decoded on a GOPbasis, the resulting motion of the image is no longer smooth. In orderto make the motion smooth, the decimation or the interpolation isrequired to be performed on a frame basis.

That is to say, a 10× fast-forward reproducing operation (or afast-forward reproducing operation performed at a speed ten times ashigh as a normal reproducing speed) is realized by reproducing one frameout of ten frames. On the other hand, a {fraction (1/10)}× slowreproducing operation is realized by displaying one and the same frame10 times in succession.

A time difference between the time when the video which is now beingreproduced was recorded (hereinafter, such a time will be referred to asa “video recording time”) and the current time, can be calculated bysubtracting the video recording time, obtained by using the timeinformation supplied from the table RAM 15, from the current time. Ifthe time difference is displayed on the TV monitor 13, the timedifference can be monitored. Before this time difference becomes zero,any arbitrary part of the video which has already been recorded can bereproduced. In addition, it is also possible to simultaneously displayon the TV monitor 13 both the time corresponding to the output of thedemodulator 3 and the time corresponding to the output of the MPEG1decoder 12 by dividing the screen into two parts. Then, a video which isnow being broadcast (and corresponds to the output of the demodulator 3)and a video which is now being reproduced (and corresponds to the outputof the MPEG1 decoder 12) can be simultaneously watched on the samescreen.

Assuming that the hard disk apparatus has a capacity large enough torecord compressed video signals corresponding to two hours, if theviewer does not start watching a program within two hours after therecording start time, the recorded signals are updated from the point oftime two hours later than the recording start time, whereby a programcorresponding to two hours preceding the time when the viewer startswatching the recorded program can always be covered. On the other hand,an update halt mode may also be selected. In such a case, a video canonly be recorded for two hours in the same way as a commonly used VTR.

Hereinafter, detailed timings of peripheral hardware of the hard diskapparatus 8 will be described with reference to FIG. 4.

The detailed configuration of the hard disk apparatus 8 is omitted inFIG. 1. A hard disk apparatus which is universally used as a peripheraldevice for a computer system can be used as the hard disk apparatus 8.The hard disk apparatus 8 may include either one disk medium or aplurality of disk media and includes a recording and reproducing head,not a head exclusively used for a recording operation or a reproducingoperation.

Portion (a) of FIG. 4 represents an output of the MPEG1 encoder 4 andA1, A2, A3, . . . A6 indicate the signals obtained by dividing theoutput by every 1.5 Mbits. Portion (b) of FIG. 4 represents theoperational modes of the recording buffer memory 5 having a capacity of200 Kbytes and W indicates writing a signal onto the memory and Rindicates reading out a signal from the memory. Thus, A1-W means writinga signal A1 onto the buffer memory and A1-R means reading out the signalA1 from the buffer memory, for example. A signal is written onto thebuffer memory in real time simultaneously with the video signals, whilethe signal is read out from the buffer memory at a high rate inaccordance with the transfer rate at which the signal is transferred tothe hard disk apparatus B.

Portion (c) of FIG. 4 represents the operational modes of the recordingbuffer memory 6 having a capacity of 200 Kbytes and W and R indicate thesame operations as those in portion (b). The buffer memories 5 and 6operate in pairs. More specifically, while one of the buffer memories 5or 6 transfers data to the hard disk apparatus 8 via the first switch 7,the other buffer memory 6 or 5 stores therein a compressed video signalsupplied from the MPEG1 encoder 4.

Portion (d) of FIG. 4 represents the seek timings for writing data ontothe hard disk apparatus 8. Portion (e) of FIG. 4 represents the timingsat which data is transferred from the buffer memories 5 and 6 to thehard disk apparatus 8 so as to be written thereon. A1-W means writingthe signal A1 onto the hard disk apparatus 8. Though the time sequenceis not specifically shown in FIG. 4, portions (b) and (c) always precedeportion (e). For example, the signal A1 read out by A1-R in portion (b)is written by A1-W in portion (e).

Portion (f) of FIG. 4 represents the seek timings for reading out datafrom the hard disk apparatus 8. Portion (g) of FIG. 4 represents thetimings at which data is read out from the hard disk apparatus 8 andB1-R means reading out a signal B1 from the hard disk apparatus 8, forexample. Portion (h) of FIG. 4 represents the operational modes of thereproducing buffer memory 9 having a capacity of 200 Kbytes and B1-Wmeans writing the signal B1 onto the buffer memory 9.

Portion (i) of FIG. 4 represents the operational modes of thereproducing buffer memory 10 having a capacity of 200 Kbytes and W and Rindicate the same operations as those described above. The buffermemories 9 and 10 operate in pairs. More specifically, while a signalread out from the hard disk apparatus 8 is written onto one of thebuffer memories 9 or 10, the other buffer memory 10 or 9 reads out asignal, which has been supplied from the hard disk apparatus 8 andstored in the buffer memory 10 or 9, at a rate of the video signal andthen supplies the signal to the MPEG1 decoder 12 via the second switch11.

Portion (j) of FIG. 4 represents an input to the MPEG1 decoder 12. Asshown in FIG. 4, the input has been extended so as to have the sameperiod as that of the output in portion (a) and is continuouslyreproduced.

As shown in FIG. 4, for recording and reproducing a video signalsimultaneously and continuously, the period of each of the signals A1,A2, A3, . . . is set to be longer than the following time T:

T=(seek time for preparing to record data onto the hard disk)

+(time required for writing the data having the

period onto the hard disk)

+(seek time for preparing to reproduce the data from the hard disk)

+(time required for reading out the data having the period from the harddisk)

If the total of these times becomes longer than the period of A1, A2,A3, . . . , then the video cannot be recorded but overflows. Thus, theperiod is required to be sufficiently longer than the total time. Sincethe seek time of the hard disk, in particular, largely varies dependingupon situations, a maximum seek time is required to be estimated andincluded in the sum.

In this case, the period of A1, A2, A3, . . . is a time during which anMPEG bit stream having a bit rate of 1.5 Mbps is occupied by a buffermemory having a capacity of 200 Kbytes: 200 k÷(1.5 M 8)=about 1 second.Assuming that the data transfer rate of the hard disk is 1 Mbyte persecond, the time required for transferring the data is: 200 k÷1 M=0.2second. Even when the maximum seek time is estimated to be 100milliseconds,

T=0.1+0.2+0.1+0.2=0.6 second<1 second

Thus, a sufficient margin time can be obtained.

As described above, the video signal recording and reproducing apparatusaccording to the present invention is a video signal recording andreproducing apparatus using a hard disk which can simultaneously performthe recording and reproducing operations in different portions of thesame hard disk. Thus, it is possible to provide an apparatus which canperform a trick play reproducing operation (e.g., a fast-forwardreproducing operation or a backward reproducing operation) of a recordedpart of a broadcast program which is now being recorded, while recordingthe broadcast program.

As a result, it is possible to start watching the recorded part of aprogram without waiting for the program to end, as is necessary in therecording and reproducing operations performed by a conventional singleVTR. In addition, even when a viewer initially starts watching a programat a time much later than the broadcast start time of the program, theviewer can finish watching the program substantially at the same time asthe broadcast end time by additionally utilizing a fast-forwardreproducing function in the middle of the reproducing operation, so thata considerable amount of time can be saved.

Furthermore, though audio signal recording and reproducing sections arenot shown in FIG. 1, a sound accompanied with a video can be processedcompletely in the same way as the video. Therefore, the same descriptionas applied to a “video” in this example is applicable to “video andsound”.

It is noted that it is possible to perform the writing operation onto ahard disk only when it is necessary while a viewer watches a TV programfor using the hard disk as long as possible. In such a case, a viewerstarts a video recording operation by pushing an instruction button. Arecording start button and a reproducing start button are provided forthe operator panel 18 or a single button can be used for these twopurposes. This function is effectively applicable to a case where aviewer cannot help stopping watching a TV program in the middle of theprogram for some unavoidable reason. For example, in the case where itbecomes necessary to stop watching a TV program in the middle forreceiving a visitor, responding to a telephone call, taking a bath orhaving a meal or the like, the viewer pushes the recording start buttonfor recording the program from that point of time, settles his businessand then pushes the reproducing start button. Thus, the recorded programis reproduced and the viewer can watch the program from the point oftime when he started recording the program without missing any scene ofthe program. In addition, by providing an end setting button forallowing a viewer to set a recording end time easily, even if the viewermust go out suddenly and does not know exactly when he will be able tocome home, the viewer can record a video for as long as he wants. Thus,the viewer can comfortably leave after he sets the hard disk in awriting state. In this case, if the end setting button is configuredsuch that the recording time can be set depending upon how many timesthe viewer pushes the button (for example, one push of the button allowsthe program which is now being watched to be recorded for 30 minutes andtwo pushes of the button allows the program to be recorded for 1 hour),then the viewer can advantageously operate this apparatus very easily.

Since the program is continuously recorded during the reproduction ofthe program, the viewer can naturally watch the part of the programwhich is being broadcast during the reproduction.

In addition, a TV signal detector (not shown in FIG. 1) for determiningwhether or not a TV broadcast is available or not is incorporated in thede modulator 3 shown in FIG. 1. A synchronizing signal detector which iscommonly provided for an existing TV receiver can be used as the TVsignal detector and it is not necessary to additionally provide a novelcircuit. Hereinafter, a case where a synchronizing signal detect or isused as the TV signal detector will be specifically described.

First, it is determined whether or not a synchronizing signal exists inthe demodulated video signal. If a synchronizing signal is absent in thedemodulated video signal, then it is determined to be out of abroadcasting time, thereby protecting the hard disk apparatus from thewriting operation. If the writing operation has already been started onthe hard disk apparatus, the writing operation onto the hard diskapparatus is temporarily suspended at a point of time when thesynchronizing signal is no longer detected and is resumed when thesynchronizing signal is detected again. As a result, it is possible toavoid performing a recording operation in an undesired time period(e.g., a midnight time or the like when no broadcast is available), sothat the lifetime of the hard disk apparatus can be lengthened. Thisfunction will be effective for avoiding performing an unnecessaryrecording operation at midnight when no broadcast is televised,supposing that a hard disk comes to have a recording capacity largeenough to always record a televised video corresponding 24 hourspreceding the current time in the near future. Since a synchronizingsignal detector is commonly available well known circuit, the detaileddescription thereof will be omitted herein. A synchronizing signaldetector of the type which integrates a synchronizing signal obtainedfrom a well known synchronizing signal separator thereby determiningwhether or not the DC level thereof is a normalized value, or asynchronizing signal detector of the type which determines whether ornot the frequency of the synchronizing signal is a predetermined value(e.g., the frequency of a horizontal synchronizing signal is 15.73 KHzin an NTSC standard) is used herein.

This example has been described while using a synchronizing signaldetector as a TV signal detector. However, in the case where a digitalbroadcast is received, the TV signal can be detected by a method inwhich it is determined whether or not an error signal detected by anerror signal detector, used for reproducing a clock for a PLL or thelike, is at a predetermined level or by a method in which it isdetermined whether or not the amount of the error flag output from anerror detector for correcting an error of a transmitted signal is at apredetermined level.

If a viewer continuously records a program and supplies a signal by thepush of a button or the like for stopping watching the program such thatthe recording stop time, the address and the like are stored; then theviewer can naturally reproduce the program from the point of time whenthe viewer stopped watching the program by pushing the reproducing startbutton for resuming watching the program.

In addition, by additionally providing a second tuner and a seconddemodulator (though not shown in FIG. 1), a channel to be watched and achannel to be recorded can be independently designated. For example, acase where a second program to be watched by a viewer starts on anotherchannel while the viewer is watching a first program to be recorded willbe assumed. In such a case, if the viewer starts to record the secondprogram on the second channel, the viewer can watch the second programfrom the beginning thereof from the point of time when the first programwhich the viewer is watching ends.

EXAMPLE 2

Hereinafter, a second example of the present invention will bedescribed. Since the fundamental configuration in the second example issubstantially the same as that in the first example shown in FIG. 1, nodrawings will be particularly referred to for describing the secondexample.

The video signal recording and reproducing apparatus of the secondexample is further provided with a circuit for inputting a video and/ora sound other than that of a broadcast (e.g., a reproduced signal of aVTR). If a part of a broadcast or desired video and/or sound inputthrough the circuit is stored in the hard disk apparatus 8 for about 10seconds and is automatically reproduced at a predetermined time everymorning, the broadcast or the video and/or the sound can be used inplace of an alarm clock so that a user can wake up comfortably.

It is noted that in such a case, the volume of the sound is required tobe automatically adjusted to a sufficiently large volume, irrespectiveof a sound volume which was set the previous day. Furthermore, byadditionally providing a speech recognition circuit for the apparatusshown in FIG. 1, the apparatus can reproduce a predetermined video byrecognizing the audible alarm of an alarm clock other than the clockincorporated in the system. Alternatively, by recognizing not an alarmbut a speech pattern such as “I'm home” when a user comes home, theapparatus can reproduce a predetermined video by reading the video fromthe hard disk apparatus 8.

Furthermore, it is true that a user is required to perform complicatedoperations for designating his desired video and/or sound. However, ifcompressed video and/or sound are/is recorded in an inexpensive mediumsuch as a floppy disk or a CD-ROM and the medium is put on the market,then the user can record his desired video and/or the sound onto thehard disk by connecting a reader for reading the video and/or sound fromthe medium to this apparatus. If the user reproduces the video and/orthe sound at a predetermined time every morning, the user can receive amorning call of his favorite actor or the like. Thus, this apparatus canalso be used as an instrument for making a user's life comfortable.

EXAMPLE 3

Hereinafter, a third example of the present invention will be described.In this third example, the hard disk apparatus shown in FIG. 1 has atleast two recording regions. The first recording region of the hard diskapparatus 8 is a recording region in which the video signal received bythe tuner 2 is recorded for realizing the function described in thesecond example. The second recording region of the hard disk apparatus 8is a recording region for saving therein the video data which hasarbitrarily been retrieved by a viewer from the video data recorded inthe first recording region. As a result, the viewer can selectively savearbitrary information from a televised program in the second recordingregion while the viewer is watching the program.

For example, if only a scene of a travel program frequently televisedrecently, in which the address, the telephone number and the like of ahotel are displayed on the screen or the contents of a dish, a serviceor the like are presented, is selectively saved in the second recordingregion, the viewer can save such information more exactly without anyneed for taking notes. In addition, if the viewer applies a file name tothe video data retrieved by himself and then stored in a prescribeddirectory, the viewer will be able to search for his desired file latermore easily.

A specific example will be described below. For example, the secondrecording region of the hard disk is divided beforehand into a pluralityof directories for “restaurants”, “travel spots”, “hotels” and the like.The directory of “hotels” can be further divided into a plurality ofsub-directories of “restaurant hotels”, “hot-spring hotels” and thelike. A viewer performs an operation for designating a start point andan end point of a video to be saved while the viewer is watching aprogram, and then selects a directory corresponding to the retrieveddata. As a result, the video data is automatically saved in the selecteddirectory. When the viewer searches for the video data later, the viewerwill be able to find the video data by selecting his desired directoryand the file name of the video data. If an external output terminal suchas an SCSI interface is provided for the hard disk apparatus for storingthe saved video data onto an external storage device such as a floppydisk drive or a PD drive, the viewer can produce his own database.

In this example, the hard disk apparatus is divided into two recordingregions for simplifying the description. Alternatively, the same effectscan also be attained by providing a circuit for designating whether thevideo data recorded on the hard disk is data which is to beautomatically updated or data which is not updated unless the viewercommands the update. For example, the hard disk apparatus can becontrolled by such a method that the type of recorded data, the sectorinformation and the like are recorded in the table RAM 15 shown in FIG.1 and the hard disk controller 14 determines whether or not therespective sectors can be updated based on the information.

EXAMPLE 4

Hereinafter, the fourth example of the present invention will bedescribed with reference to FIG. 5. In FIG. 5, since the referencenumerals 1 to 18 denote the same components as those having the samereference numerals in the first example, the description thereof will beomitted herein. In addition, since the reference numerals 9 to 26correspond to and have the same configurations as the reference numerals4 to 7 and 9 to 12 in FIG. 5, respectively, the description thereof willalso be omitted herein. In FIG. 5, the reference numeral 27 denotes aframe decimator; 28 denotes a frame interpolator; and 29 denotes a thirdswitch.

The hard disk apparatus 8 has at least two recording regions. The firstrecording region is a region in which the video signal received by thetuner 2 is recorded and which realizes the function described in thefirst example. Assuming that the first recording region has a capacitylarge enough to record compressed video signals corresponding to twohours, if the viewer does not start watching a program within two hoursafter the recording start time, the video data which was recordedpreviously is updated from the point of time, whereby a videocorresponding to two hours preceding the time when the viewer startswatching the recorded video can always be watched as a normal video asalready described in the first example.

In this example, when the video data is updated, the previously recordedvideo data is once read out; passed through the buffer memories 23 and24; and then decoded by the decoder 26 into the original video signals.Then, a frame decimator 27 performs frame decimation processing withrespect to these decoded video signals, thereby reducing the amount ofdata. The output of the frame decimator 27 is compressed again by theencoder 19. The compressed video signal, a part of the frames of whichhave been decimated in this way, are saved in the second recordingregion. The resulting recordable time is varied depending upon themethod for decimating the frames. For example, assuming that thecompression is performed by extracting one frame out of four frames, arecordable time four times as long as the recordable time in the case ofrecording a normally compressed video signal can be secured by using thesame recording capacity. That is to say, when a hard disk apparatushaving a recording capacity large enough to record data corresponding to2.5 hours by a normal recording operation is used, the viewer can watcha broadcast preceding the recording start time by about four hours(i.e., two hours in the first recording region and two hours in thesecond recording region) and check the contents of the broadcast. As aresult, the viewer can confirm a larger amount of the contents of theprograms while using a smaller recording capacity. In other words, whilereducing the required minimum recording capacity of a hard diskapparatus, it is also possible to meet the viewer's demand for recordinga video as long as possible.

It is natural that the audio signals recorded in the second recordingregion are normally recorded without performing a decimation operationon a frame basis. When the video signals recorded in the secondrecording region are read out to be displayed on the TV monitor 13, theoutput of the decoder 12 shown in FIG. 5 is once input to the frameinterpolator 28, where the decimated frames are interpolated by the sameframes and the interpolated signals are passed through the third switch29 so as to be displayed on the TV monitor 13. In this example, a framedecimation method is used for reducing the amount of video data.Alternatively, various other methods such a sampling method and a colordifference signal elimination method can also be used.

In this example, the hard disk apparatus is divided into two recordingregions for simplifying the description. However, a circuit for applyinginformation for identifying whether the video data recorded on the harddisk is data composed of normally recorded video signals, or data havinga reduced amount of data by a frame decimation or the like to the videodata recorded on the hard disk, and saving the data including theidentifiers on the hard disk, may be provided. For example, it ispossible to utilize a method in which the type of recorded data, thesector information and the like are recorded in the table RAM 15 shownin FIG. 5 and the hard disk controller 14 controls the hard diskapparatus 8 based on the information.

In addition, the viewer can independently set a time period during whicha video signal is normally recorded and a time period during which datais recorded after the amount of the data is reduced by a framedecimation or the like. As a result, the viewer can utilize theapparatus of the invention so as to satisfy his own preferences morecompletely.

EXAMPLE 5

Hereinafter, the fifth example of the present invention will bedescribed. Since the fundamental configuration used in this example isthe same as that shown in FIG. 1, there are no drawings exclusively usedfor describing this example. If a plurality of (i.e., a number N of)tuners having the same configuration as the tuner 2 shown in FIG. 1 areprovided, a plurality of video signals can be simultaneously received. Anumber N of encoders 4 may be provided. Alternatively, if an encoder ofthe type operating at an encoding rate N times as high as a normalencoding rate is used, then it is possible to use the encoder byswitching it depending upon the time.

If a number N of hard disk apparatuses having the same configuration asthat of the hard disk apparatus 8 shown in FIG. 1 are used in parallel;if the reading and writing rates from/onto the hard disk apparatus 8 areset to be higher while using a single hard disk apparatus 8 in the sameway as in FIG. 1; or if the period A1, A2, A3, . . . or the capacity ofthe buffer memories is increased such that the time T_(N) required forreading and writing in the N channels becomes shorter than the period,then it is possible to read out a video on a desired channel whilesimultaneously writing videos on the N channels. By realizing thisfunction, a viewer can select his desired another TV channel after a TVprogram on a channel to be watched is finished without designating theanother channel beforehand.

EXAMPLE 6

Hereinafter, the sixth example of the present invention will bedescribed with reference to FIG. 6. In FIG. 6, since the referencenumerals 1 to 18 denote the same components as those having the samereference numerals in the first example, the description thereof will beomitted herein.

In FIG. 6, the reference numeral 30 denotes a screen synthesizer; 31denotes a screen separator; and 32 denotes a pixel interpolator. In thisexample, by providing a plurality of (e.g., four in FIG. 6) tuners 2 anddemodulators 3, a plurality of video signals can be simultaneouslyreceived. The received video signals are input to the screen synthesizer30. The screen synthesizer 30 matches the phases of the synchronizingsignals of the respective video signals by using frame memories (notshown) and then reduces the sizes of the screens corresponding to therespective video signals by performing a pixel decimation, a linedecimation and the like, thereby synthesizing the screens having reducedsizes into one screen as shown in FIG. 7. A composite video signalobtained by synthesizing the video signals in the above-described manneris compressed by the encoder 4 and then recorded onto the hard diskapparatus 8 in the same way as in the first example. In performing areproducing operation, the screen separator 31 extracts only the portioncorresponding to the desired channel from the synthesized screen and thepixel interpolator 32 performs a pixel interpolation and a lineinterpolation on the extracted portion for enlarging the size of theportion to that of a normal screen and then displays the video on the TVmonitor 13, as shown in FIG. 8. FIG. 8 is a diagram illustrating anoperation of retrieving only the video in the desired channel from thereproduced video. As a result, videos on a larger number of TV channelscan be recorded in the hard disk apparatus 8 having the same recordingcapacity as that of a conventional one. In addition, by reading out avideo on a desired channel while simultaneously writing videos on the Nchannels, a viewer can select his desired another TV channel after a TVprogram on a channel to be watched is finished without designating theanother channel beforehand. Furthermore, in this sixth example, it isnot necessary to use an N-times-larger recording capacity for recordingthe videos in the N channels, unlike the third example, so that it iseffectively possible to save the recording capacity of the hard diskapparatus.

It is naturally possible to directly display the composite video signaloutput from the decoder 12 without performing a screen separation.

In the foregoing examples, a recording format (or a relationship betweena GOP unit and a sector unit on the hard disk, in particular) has notbeen specifically described. However, in view of the case of performinga trick-play reproducing operation such as a fast-forward reproducingoperation, it is preferable to utilize a format in which a simplerelationship is established between a GOP and a sector. For example, aformat in which one GOP consists of a number K of sectors; a format inwhich one sector consists of a number M (where K and M are integers) ofGOPs; a format in which a number K of sectors correspond to a number Mof GOPs; or the like can be used.

In addition, if the hard disk apparatus of the present invention isconfigured as a hard disk apparatus having a removable drive portionwhich is currently used as a peripheral device for a personal computer,then the hard disk apparatus of the present invention can beadvantageously used for forming a backup file of video data, savingparticular video data and the like.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

What is claimed is:
 1. An apparatus for recording a video signalincluding a plurality of frames onto a hard disk apparatus andreproducing the video signal recorded onto the hard disk apparatus,comprising: receiving means for receiving a video signal; compressionmeans for compressing an amount of information per a unit of M frames ofthe received video signal so as to output a compressed video signal;time compression means for compressing an amount of time per a unit ofN*M frames of the compressed video signal along a time axis so as toobtain a compressed video writing signal; writing means for writing thecompressed video writing signal onto a plurality of different portionsof the hard disk apparatus via a magnetic head, each of the plurality ofdifferent portions having successive L sectors, N*M frames of thecompressed video writing signal being written onto the successive Lsectors; reading means for reading an arbitrary compressed video writingsignal, which was previously written onto the plurality of differentportions of the hard disk apparatus, from the hard disk apparatus viathe magnetic head to obtain a compressed video reading signal; timedecompression means for decompressing an amount of time per a unit ofN*M frames of the compressed video reading signal along the time axis soas to obtain a decompressed video signal for reproduction; decodingmeans for decompressing an amount of information per a unit of M framesof the decompressed video signal for reproduction; and control means forcontrolling the writing means and the reading means such that a periodduring which the compressed video writing signal is written onto thehard disk apparatus does not overlap with a period during which thecompressed video reading signal is read from the hard disk apparatus,where L, M and N each is an integer greater than or equal to 1, whereina period for the compressed video signal which is output from thecompression means is set to be longer than time T. where the time T isdefined as a sum of seek time required for moving the magnetic head towrite the compressed video writing signal onto the hard disk apparatus,time required for writing the compressed video writing signal onto thehard disk apparatus, seek time required for moving the magnetic head toread the compressed video reading signal from the hard disk apparatus,and time required for reading the compressed video reading signal fromthe hard disk apparatus.
 2. An apparatus according to claim 1, whereinthe receiving means further receives an audio signal.
 3. An apparatusaccording to claim 1, wherein the M frames of the received video signalcorresponds to one GOP.
 4. An apparatus according to claim 1, whereinthe compressed video writing signal which is written onto the hard diskapparatus at an earlier time is updated by a newly obtained compressedvideo writing signal.
 5. An apparatus according to claim 1, furthercomprising instruction means for starting and/or finishing recording avideo signal onto the hard disk apparatus.
 6. An apparatus according toclaim 1, wherein the instruction means for starting recording a videosignal onto the hard disk apparatus is driven manually.
 7. An apparatusaccording to claim 5, wherein the instruction means for startingrecording a video signal onto the hard disk apparatus is driven by timermeans.
 8. An apparatus according to claim 5, wherein the instructionmeans for finishing recording a video signal onto the hard diskapparatus is driven by timer means.
 9. An apparatus according to claim1, further comprising instruction means for starting and/or finishingreproducing the recorded video signal from the hard disk apparatus. 10.An apparatus according to claim 1, wherein the instruction means forstarting reproducing the recorded video signal from the hard diskapparatus is driven manually.
 11. An apparatus according to claim 1,further comprising display means for displaying the decompressed videosignal.
 12. An apparatus according to claim 11, wherein the displaymeans further displays a time difference between a time at which a videosignal which is being reproduced was recorded and a current time.
 13. Anapparatus according to claim 11, wherein the display means furtherdisplays a time at which a video signal which is being reproduced wasrecorded and a current time.
 14. An apparatus according to claim 11,wherein the display means further displays the received video signal andan output of the decoding means, simultaneously.
 15. An apparatusaccording to claim 3, further comprising operation means for selectivelysetting one of a normal reproduction mode, a fast forward reproductionmode, a backward reproduction mode and a slow reproduction mode as areproduction mode.
 16. An apparatus according to claim 15, furthercomprising frame decimation means for decimating a frame from decodedvideo signal decoded from GOP signal which is reproduced from the harddisk apparatus when the operation means sets one of the fast forwardreproduction mode and the backward reproduction mode.
 17. An apparatusaccording to claim 15, further comprising frame interpolation means forinterpolating a frame from decoded video signal decoded from GOP signalwhich is reproduced from the hard disk apparatus when the operationmeans sets the slow reproduction mode.
 18. An apparatus according toclaim 1, further comprising television signal detection means fordetecting a normal television signal as the video signal received by thereceiving means, wherein the writing of the compressed video writingsignal onto the hard disk apparatus is enabled only when the televisionsignal detection means has detected the normal television signal.
 19. Anapparatus according to claim 1, further comprising speech recognitionmeans for recognizing a speech, wherein the control means controls thereading means such that a predetermined compressed video reading signalis read from the hard disk apparatus in response to the recognition ofthe speech.
 20. An apparatus according to claim 1, wherein the controlmeans controls the writing means such that a part of the compressedvideo writing signal is selected and written onto the hard diskapparatus with information for prohibiting overwriting data onto thehard disk apparatus in response to an input from a user.
 21. Anapparatus according to claim 20, wherein the selected part of thecompressed video writing signal is accompanied with information which isused to search the selected part of the compressed video writing signalduring reproduction.
 22. An apparatus according to claim 20, wherein thecontrol means further controls transfer of the selected part of thecompressed video writing signal to another apparatus.
 23. An apparatusaccording to claim 1, further comprising a decimating means fordecimating a part of the reproduced video signal, wherein thecompression means compresses the amount of information per a unit of Mframes of the decimated reproduced video signal.
 24. An apparatusaccording to claim 1, wherein the receiving means receives a pluralityof video signals from a plurality of channels, the compression meanscompresses the amount of information per a unit of M frames of each ofthe received plurality of video signals from the plurality of channelsso as to output the compressed video signal.
 25. An apparatus accordingto claim 1, wherein the receiving means receives a plurality of videosignals from a plurality of channels, the apparatus further comprises asynthesis means for synthesizing the plurality of video signals receivedfrom the plurality of channels into a synthesized signal, thecompression means compresses the amount of information per a unit of Mframes of the synthesized signal.
 26. An apparatus according to claim 1,wherein the receiving means receives a plurality of video signals from aplurality of channels.